Filmes nanométricos de FeN e ALN crescidos por sputtering e aplicações do efeito peltier

This study will show the capability of the reactive/nonreactive sputtering (dc/rf) technique at low power for the growth of nanometric thin films from magnetic materials (FeN) and widegap semiconductors (AlN), as well as the technological application of the Peltier effect using commercial modules of bismuth telluride (Bi2Te3). Of great technological interest to the high-density magnetic recording industry, the FeN system represents one of the most important magnetic achievements; however, diversity of the phases formed makes it difficult to control its magnetic properties during production of devices. We investigated the variation in these properties using ferromagnetic resonance, MOKE and atomic force microscopy (AFM), as a function of nitrogen concentration in the reactive gas mixture. Aluminum nitride, a component of widegap semiconductors and of considerable interest to the electronic and optoelectronic industry, was grown on nanometric thin film for the first time, with good structural quality by non-reactive rf sputtering of a pure AlN target at low power (≈ 50W). Another finding in this study is that a long deposition time for this material may lead to film contamination by materials adsorbed into deposition chamber walls. Energy-dispersive X-ray (EDX) analysis shows that the presence of magnetic contaminants from previous depositions results in grown AlN semiconductor films exhibiting magnetoresistance with high resistivity. The Peltier effect applied to commercially available compact refrigeration cells, which are efficient for cooling small volumes, was used to manufacture a technologically innovative refrigerated mini wine cooler, for which a patent was duly registered

Estudos de modelos Estocásticos: processo de contato, séries aleatórias e processos difusivos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Experimental dermatophytosis in hamsters inoculated with Trichophyton mentagrophytes in the cheek pouch

Esse estudo apresenta os resultados obtidos quando da inoculação de Trychophyton mentagrophytes na bolsa jugal do hamster, local imunologicamente privilegiado. Foram utilizados 42 animais: 21 inoculados com 10(6) fungos na bolsa jugal (grupo 1) e, 21 inicialmente inoculados com 10(6) fungos no coxim plantar e, 15 dias após, na bolsa jugal com a mesma quantidade fúngica (grupo 2). Os animais foram sacrificados às 20 h, 3, 7, 14, 30, 60 e 120 dias; foram coletadas amostras da bolsa jugal inoculada, e das patas submetidas ao teste do coxim plantar (TCP). Independente do grupo e do tempo de evolução da infecção, os animais não desenvolveram hipersensibilidade tardia avaliada através do TCP. A pré-inoculação de fungos no coxim plantar não alterou a morfologia das lesões induzidas na bolsa jugal. Assim, nos animais do grupo 1 e grupo 2, a introdução do fungo na bolsa jugal, resultou em lesão focal, constituída por infiltrado inflamatório agudo estéril, com formação de abscesso, que evoluiu para reação macrofágica e, posteriormente, para a resolução mesmo na ausência de resposta imune detectável pelo TCP. Nossos resultados indicam que, apesar do importante papel da resposta imune na regressão espontânea da dermatofitose, outros fatores são, também, parte integral da defesa contra esta infecção fúngica.

Análise da genotoxicidade das águas da Lagoa da Extremoz - RN

The contamination of the waters resources for wastewater from industrial, agricultural, and domestic sources is a serious environment problem, compromising its use for human consumption and agriculture. The Extremoz-RN Lake is an important freshwater source for the supply of the city of Natal, supplying a population of approximately 160,000 habitants. This aquatic body is located near an industrial pole which can be a serious risk factor for quality of its waters. The objectives of this study were examined the genotoxicity of Extremoz Lake between September of 2006 and January of 2008, by a combination of the Allium micronucleus test, piscine micronucleus test and the comet assay in erythrocytes from peripheral blood of Oreochromis niloticus. Additionally, the level of eight different heavy metals was quantified through spectrometry of atomic absorption of flame. The Allium test did not detect increase in the frequencies of micronucleus in none of the analyzed periods, however a strong cytotoxic activity was demonstrated for decrease in mitotic index in the analyses carried in April and July of 2007. Negative results had been detected in the frequencies of micronucleus in O. niloticus. A statistic significant increase was observed in the levels of DNA damage in comet assay carried in July of 2007. The results of the chemical analysis had detected increase in the levels of cadmium, chromium, copper, nickel, lead and zinc in different periods. These results demonstrated an alteration of the water s quality of the Extremoz Lake caused for the contamination for heavy metals and increase of DNA strand breaks. The use of biomonitoring program of the heavy metal and other pollutants with genotoxic potential combinated with genotoxicity assays is recommends.

Estudos ecogenômicos e bioprospectivos de Shewanella ssp

Bacteria trom Shewanella and Geobacter ganera are the most studied iron-reducing microorganisms particularly due to their electron transport systems and contribution to some industrial and environmental problems, including steel corrosion, bioenergy and bioremediation of petroleum-impacted sites. The present study was focused in two ways: the first is an in silico comparative ecogenomic study of Shewanella spp. with sequenced genomes, and the second is an experimental metagenomic work to detect iron-reducing Shewanella through PCR-DGGE of a metabolic gene. The in silico study resulted in positive correIation between copy number of 16S rDNA and genome size in Shewanella spp., with clusters of rrn near lhe origin of replication. This way, the genus is inferred as opportunist. There are no compact genomes and their sequences length varied, ranging from 4306142 nt in S. amazonensis SB2B to 5935403 nt in S. woodyi ATCC 51908, without correIation to temperature range characteristic of each specie. Intragenomic 16S rDNA sequences possess little divergence, but reasonable to resuIt in different phyIogenetic trees, depending on the sequence that is chosen to compare. For moIecuIar detection of iron-reducing Shewanella, it is proposed the mtrB gene as new biomarker. because it codes to a fundamental protein at Fe (III)-reduction. The specific primers were designed and evaluated in silico and resulted in a fragment of 360 pb. In the second study, these primers were tested in a genomic sample from S. oneidensis MR-1, amplifying the expected region. After this successfuI resuIt, the primer set was used as a tool to assess the iron-reducing communities of ShewaneIla genus under an environmental stress, i.e. crude oil contamination in mangrove sediment in Rio Grande do Norte State (Brazil). The primers presented high specificity and the reactions performed resulted in one single band of ampIification in the metagenomic samples. The fingerprinting obtained at DGGE reveaIed temporal variation of Shewanella spp. in analyzed samples. The resuIts presented show the detection of a biotechnological important group of microorganisms, the iron-reducing Shewanella spp. using a metabolic gane as target. It is concluded there are eight or more 16S rDNA sequences in Shewanella genus, with little divergence among them that affects the phylogeny; the pair of primers designed to ampIify mtrB sequences is a viable alternative to detect iron-reducing ShewanelIa in metagenomic approaches; such bacteria are present in the mangrove sediment anaIyzed, with temporal variations in the samples. This is the first experimental study that screened the iron-reducing Shewanella genus in a metagenomic experiment of mangrove sediments subjected to oil contamination through a key metabolic gene

Avaliação da genotoxicidade das águas sueprficiais da Barragem Engenheiro Armando Ribeiro Gonçalves, Assu/RN

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Aplicação integrada de métodos geofísicos em uma área de disposição de resíduos sólidos urbanos em Bauru-SP

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Parâmetros parasitológicos e desempenho produtivo de ovinos naturalmente infectados com nematoides gastrintestinais mantidos em diferentes pastagens tropicais

The control of gastrointestinal nematodes of small ruminants is usually done with anthelmintics. However, due to the emergence of ever-increasing parasite resistance to these drugs, looking up an alternative control parasites. One of this is sought in pasture management, as these are the sources of animals` infection by L3 infective larvae of helminths. The aim of this study was to evaluate the performance of sheep to natural infections by gastrointestinal nematodes grazing Panicum maximum cv. Massai and cv. Aruana, and Brachiaria brizantha cv. Piatã and cv. Marandu. The work was conducted from May to August-2011 with 48 male sheeps SRD versus Santa Inês breed. The animals were naturally infected with gastrointestinal nematodes, and maintained in four different cultivars of tropical forage grasses, naturally contaminated with eggs and larvae of gastrointestinal nematodes. Each week the animals were phenotypically characterized by parasitological examinations (eggs per gram of feces - EPG, and feces culture), hematological (packed cell volume PCV, and blood eosinophil count) method to evaluate the Famacha© colorof ocular mucosa, and the measures of body condition score and weight. In pastures was made the recovery of infective larvae in order to determine the quantity of L3 present in the pasture. The experimental design was a randomized completed block with two replications and before the entry of animals in the paddocks, they have been wormed. The experiment was ended when the animals reached 32.0 kg liveweight, and then were slaughtered and autopsies performed for the recovery and identify parasites of the abomasum, small intestine and large intestine. Results were subjected to analysis of variance, t test and Tukey`s test. The animals kept on pastures of Marandu grass had lower EPG counts, higher percentage of packed cell volume and higher average weight; those who remained in the Piatã pasture had lower eosinophil counts per microliter of blood. About the Famacha©, the highest prevalence was Famacha 2, and the body condition score ranged between 2 and 3. The results of feces cultures and recovery of larvae on pastures showed the presence of larvae of Trichostrongylus sp., and at the necropsy too. This way, it was concluded that the grass cultivars influences the sheep parasite load; the Famacha, together with EPG and packed cell volume are important indicators for use in controlling gastrointestinal nematode infections. The Trichostrongylus sp. was the most prevalent parasite in sheep during the rainy season

Desenvolvimento de uma metodologia para caracterização de amostras de sedimento: Rio Jundiaí RN

The study of sediment in water bodies presents great environmental importance, because of its ability to adsorb the pollutants, they may facilitate the understanding of the history of the current quality of the water system. Depending on how it is done the collection, analysis can show both a recent contamination as old. The detailed characterization of the sediment may reveal details that can understand how each type of pollutant interacts with the material given its composition. In this work it has developed a systematic methodology to characterize samples of sediment, with the aim to understand how a series of metal is distributed in different size fractions of the sediment. This study was conducted in five samples of sediment (P1, P2, P3a, P3B and P3c) collected in Jundiaí river, one of the most important tributaries of the river Potengi in the region of Macaíba, RN. The characterization was made with the samples previously sieved into meshes with different granulometries (+8#, -8+16#, -16+65# - 65+100#,-100+200#,-200+250# and -250#), using the following techniques: Analysis of specific surface area by BET method, determining the levels of organic matter (OM%) and humidity through the gravimetry and Analysis Thermogravimetric (TG), Infrared Spectroscopy in a Fourier transform (FTIR ), Analysis of X ray diffraction (XRD), analysis of heavy metals by optical emission spectrometry with the Argon Plasma (ICP-OES). The analyzed elements were Al, Cd, Cr, Cu, Fe, Mn, Ni, Zn and P. In addition to the techniques of characterization above, was also made the rebuilding of the samples P1, P2 and P3B in relation to the levels of organic matter and concentration of heavy metals. Then, the results of the recomposed samples were compared with those obtained in crude samples, showing great consistency. The gravimetry, used in determining the levels of organic matter, was not considered an appropriate method because the clay minerals present in the sediment samples analyzed fall apart in the same range of temperature (550-600 0C) used in roasting (600 0C). The results also showed the trend of organic matter and heavy metals to focus on the thin fractions, although the largest concentrations of metals are in intermediate fractions

Avaliação das condições química e física dos sedimentos do estuário Jundiaí-Potengi

The aim of this study was to quantify the presence of major and minor elements in the sediments of the Jundiaí-Potengi estuary, bordering the municipalities of Macaíba, Natal and São Gonçalo do Amarante in the state of Rio Grande do Norte, Brazil, considering the evidence of anthropic activity along this estuary, resulting in pollution by treated and untreated wastewaters as well as those produced by industry and shrimp farming. The assessment of the environmental status of this estuary was based on physical-chemical parameters, such as granulometry, organic matter and the major (Al, Fe, Mn and P) and minor (Cd, Cr, Cu, Ni, Pb and Zn) elements found in sediment samples. Two collections were made at 12 georeferenced points along the channel of the estuary at different times. Granulometric analysis was carried out and the percentage of organic matter was determined. The sediments were microwave digested using acid digestion and quantitative analyses of the elements Al, Fe, Cd, Cr, Cu, Mn, Ni, P, Pb and Zn were performed by inductively coupled plasma optical emission spectrometry. Sediment analysis followed the methodology proposed by US EPA 3051A for total elements analysis. The small correlation between the organic matter and the elements studied here suggests that they are of geochemical rather than anthropic origin. The analytical results obtained from the bottom sediment samples in the study area show that the concentration of elements was below the reference values for standard shales (Turekian & Wedepohl, 1961) at the vast majority of points analyzed, ruling out a possible contamination by metals

Estudo dos principais fatores que influenciam na solubilização dos hpas em águas

Polycyclic aromatic hydrocarbons (PAHs) constitute a family of compounds characterized by having two or more condensed aromatic rings and for being a class of substances that are widely distributed in the environment as a complex mixture, being very persistent in the environment due to its low solubility in water. The application of chemometric methods to analytical chemistry has provided excellent results in studying the solubility of PAHs in aqueous media in order to understand the mechanisms involved in environmental contamination. The method consists in analyzing the solubilization of PAHs from diesel oil in water varying parameters such as stirring time, volume of oil added and pH, using a full factorial design of two levels and three factors. PAHs were extracted with n-hexane and analyzed by fluorescence spectroscopy because they have molecular characteristics fluorescent due to the large number of condensed rings and links, and gas chromatography coupled to a mass spectrometer (GC-MS). The results of fluorescence analysis showed that only the stirring time and pH influenced the solubility of PAHs in diesel fuel. How is a non-selective technique for the study of fluorescence was performed on form and semi-quantitative. And for the chromatographic analysis the results showed that the solubility of the different PAHs is influenced differently so that you can classify them into groups by the results of the effects

Otimização de metodologias para determinação de hidrocarbonetos policíclicos aromáticos:aplicação em água do Rio Potengi

This work aims to detect polycyclic aromatic hydrocarbons (PAHs) through optimized analytical techniques, such as gas chromatography with flame-ionisation detector (CGFID), gas chromatography coupled to mass spectrometry (CGMS), Fluorescence Spectroscopy of Molecular and Purpot of oils and greases (POG). Apply to chemometrics, Factorial Planning 23, in the preparation of samples by liquid-liquid extraction. The sample preparation was used for liquid-liquid extraction and factors in this sample was used for the application of factorial planning 23, such as the use of ultrasound, solvents (dichloromethane, hexane and chloroform) and ratio of solvent / synthetic sample. These factors were assigned two types of levels: positive and negative. It was used to form the cube to better analyze the answers. The responses of the eight combinations were obtained in reading the spectrofluorimetric. The optimization of equipment were used, and they served in the HPA's identification of the samples collected in Rio Potengi. The optimization of the equipment was observed every 16's and PAH in the samples was found that the HPA's came from contamination of the Rio Potengi. The contamination comes through organic household waste, hospital waste, and among other contamination that comes from industries that are installed around the River The factorial design of high validity, it was observed a more effective sample preparation. The factorial design of liquid-liquid extraction showed a way to spend less solvent in less time using an ideal solvent, but also a way to extract more analyte from the matrix itself is water. In planning a smaller form factor extraction was the use of ultrasound, the ratio 1:3 corresponding to a solvent and sample 3 and the best solvent was dichloromethane who presented a viable extraction, not discarding the possibility of using also the hexane. The chloroform and may be toxic not had a good extraction

Assinaturas antropogênicas de elementos maiores e traços em poeira urbana na cidade do Natal-RN

Although there are many studies on urban dust contamination by heavy metals in developed countries, little attention has been paid to this type of study in developing countries, including Brazil. Therefore, a series of investigations were performed to provide signatures of heavy metals in urban dust and assess the potential sources in the city of Natal - RN-Brazil. The fraction of these sediments was studied to pass through a sieve of 63 micrometers. For the study analyzed two groups of samples, one collected in September 2009 at the end of the rainy season (9 samples) and one collected in January 2010 in the dry season (21 samples). So in all, thirty sediment samples were collected from the street. Then, in Fluorescence Spectrometry X-rays were determined major elements SiO2, Na2O, K2O, Al2O3, MgO, P2O5, Fe2O3, MnO, TiO2 and CaO, and trace Rb, Cr, Ni, Cu, Zn, Sr and Pb by an ICPOES was determined Zn, V, Na, K, Ni, Mn, Mg, P, Fe, Cr, Cu, Pb, Ba, Ca and Al from leaching HCl 0.5 mol L-1 . The results of the concentrations of elements show that the greater presence of these occurs in the dry season, except for Si which is higher in the rainy season. Analyses by geoaccumulation Index (IGEO) Enrichment Factor (EF), Contamination Factor (CF), analysis correlation and Hierarchical Cluster, confirm that Zn, Cu and Pb is anthropogenic character. Zinc may be derived from various sources related to motor vehicles or the road signs and street grids. The elements Na, K, Mg and Ca may be related to droplets suspended in air containing cations and anions present in seawater (salty), common in Christmas throughout the year, brought by winds SE-NW. The elements Na, Mg, Ca and K are the most abundant in seawater and were analyzed in this study. This indicates that the source of these additional elements detected by analyzing the contamination factor may be the very sea. Moreover, Ni, Fe, Cr and Ba can be either as a source of anthropogenic geogênica. The source of Ca is different, because it comes in lime and paint (painting guides of buildings and streets) in construction materials, but may also be present in sediments in the fragments of shells or carbonate bioclasts common in the coastal area

Avaliação oxidativa do biodiesel de pinhão manso em diferentes processos de purificação

The objective of this study was to analyze the oxidative stability of biodiesel from jatropha obtained from different purification processes, three wet processes with different drying (in a vacuum oven, conventional oven and in anhydrous sodium sulfate) and dry (purification with magnesium silicate adsorbent). Raw materials of different qualities (jatropha crop ancient and recent crop) were used. The Jatropha oil was extracted by mechanical extraction and refined. The Jatropha biodiesel was obtained by the transesterification reaction in ethyl route using alkaline catalysis. The biodiesel samples were characterized by analysis of water content, carbon residue, Absorption Spectroscopy in the Infrared Region and Thermogravimetry. Thermogravimetric curves of purified PUsv* PUsq* and had higher initial decomposition temperatures, indicating that the most stable, followed by samples PU* and PUSC*. Besides the sample SP* is a smaller initial temperature, confirming the sample without purification to be less thermally stable. The percentage mass loss of the purified samples showed conversion of about 98.5%. The results of analyzes carbon residue and infrared suggested that contamination by impurities is the main factor for decreased oxidative stability of biodiesel. The oxidative stability was assessed from periodic monitoring, using the techniques of Rancimat, peroxide index, acid value and Pressurized Differential Scanning Calorimetry. Samples of biodiesel from jatropha which showed better oxidative stability were of the best quality raw material and wet scrubbing: PUsq* with dry chemical, using anhydrous sodium sulfate and PUsv* with vacuum drying, which had oxidative stability 6 hours in Rancimat time 0 days, within the limits established by the Technical Regulation No. 4/2012 of the ANP, without the addition of antioxidant, suggesting that these procedures the least influence on the oxidative stability of biodiesel

Uso da espectroscopia do infravermelho próximo e técnicas multivariadas para diferenciar escherichia coli e salmonella enteritidis inoculadas em polpa de fruta (abacaxi)

Aiming to consumer s safety the presence of pathogenic contaminants in foods must be monitored because they are responsible for foodborne outbreaks that depending on the level of contamination can ultimately cause the death of those who consume them. In industry is necessary that this identification be fast and profitable. This study shows the utility and application of near-infrared (NIR) transflectance spectroscopy as an alternative method for the identification and classification of Escherichia coli and Salmonella Enteritidis in commercial fruit pulp (pineapple). Principal Component Analysis (PCA), Independent Modeling of Class Analogy (SIMCA) and Discriminant Analysis Partial Least Squares (PLS-DA) were used in the analysis. It was not possible to obtain total separation between samples using PCA and SIMCA. The PLS-DA showed good performance in prediction capacity reaching 87.5% for E. coli and 88.3% for S. Enteritides, respectively. The best models were obtained for the PLS-DA with second derivative spectra treated with a sensitivity and specificity of 0.87 and 0.83, respectively. These results suggest that the NIR spectroscopy and PLS-DA can be used to discriminate and detect bacteria in the fruit pulp